Search for anticonvulsant and analgesic active derivatives of dihydrofuran-2(3H)-one

Overview of Chemistry and Therapeutic Potential of Non-Nitrogen Heterocyclics as Anticonvulsant Agents

Epilepsy is a chronic neurological disorder, characterized by the predisposition of unprovoked seizures affecting the neurobiological, psychological, cognitive, economic, and social wellbeing of the patient. As per the 2019 report by World Health Organization, it affects nearly 80% of the population, which comes from middle to low-income countries. It has been suggested that 70% of such cases can be treated effectively if properly diagnosed. It is one of the most common neurological diseases affecting 50 million people globally. Most of the antiepileptic drugs used in clinical practice are only 60-80% effective in controlling the disease. These drugs suffer from serious drawbacks of non-selectivity and toxicity that limit their clinical usefulness. Hence, there is a need to search for safe, potent, and effective anti-epileptic drugs. One of the emerging strategies to discover and develop selective and non-toxic anticonvulsant molecules focuses on the design of non-nitrogen heterocyclic compounds (NNHC). Drugs such as valproic acid, gabapentin, viagabatrin, fluorofelbamate, tiagabine, progabide, pregabalin, gamma amino butyric acid (GABA), etc. do not contain a nitrogen heterocyclic ring but are as effective anticonvulsants as conventional heterocyclic nitrogen compounds. This review covers the various classes of NNHC which have been developed in the recent past as anticonvulsants along with their chemistry, percentage yield, structure-activity relationship and biological activity. The most potent compound in each series has been identified for comparative studies, for further structural modification and to improve the pharmacokinetic profile. Various optimized synthetic pathways and diverse functionalities other than nitrogen-containing rings discussed in the article may help medicinal chemists to design safe and effective anticonvulsant drugs in near future.

Dinuclear zinc-catalyzed asymmetric [3 + 2] cyclization reaction for direct assembly of chiral α-amino-γ-butyrolactones bearing three stereocenters

A highly atom-economic and novel enantioselective [3 + 2] cyclization reaction for the construction of optical α-amino-γ-butyrolactones possessing three stereocenters.

Synthesis of α-Benzyloxyamino-γ-butyrolactones via a Polar Radical Crossover Cycloaddition Reaction

A direct catalytic synthesis of substituted α-benzyloxyamino-γ-butyrolactones is reported, starting from simple oxime acids and alkenes. The substituted O-benzyloxime acid starting materials are cyclized with oxidizable alkenes, via Polar Radical Crossover Cycloaddition (PRCC) reactions. The catalytic reaction is carried out using the Fukuzumi acridinium photooxidant and substoichiometric amounts of a redox-active cocatalyst. The utility of this method has been demonstrated through the use of 3 oxime acids and 19 oxidizable olefins.

Piperazine scaffold: A remarkable tool in generation of diverse pharmacological agents

Piperazine is one of the most sought heterocyclics for the development of new drug candidates. This ring can be traced in a number of well established, commercially available drugs. Wide array of pharmacological activities exhibited by piperazine derivatives have made them indispensable anchors for the development of novel therapeutic agents. The review herein highlights the therapeutic significance of piperazine derivatives. Various therapeutically active piperazine derivatives developed by several chemists are reported here.

3-[4-(3-Trifluoromethyl-phenyl)-piperazin-1-yl]-dihydrofuran-2-one and pregabalin attenuate tactile allodynia in the mouse model of chronic constriction injury

PURPOSE

There is a strong medical demand to search for novel, more efficacious and safer than available, analgesics for the treatment of neuropathic pain. This study investigated antinociceptive activity of intraperitoneally administered 3-[4-(3-trifluoromethyl-phenyl)-piperazin-1-yl]-dihydrofuran-2-one (LPP1) and pregabalin in the chronic constriction injury (CCI) model of neuropathic pain in mice and evaluated these drugs' influence on motor coordination. In addition, microscopic examinations of the sciatic nerve were performed to assess, if a surgical method or drug treatment caused changes in the structure of this nerve. Moreover, the alterations of nerve growth factor (NGF) content after drug treatment were assessed.

METHODS

Antiallodynic and antihyperalgesic activities of LPP1 and pregabalin were assessed in the von Frey and hot plate tests. Motor-impairing properties were evaluated in the rotarod test. Microscopic examinations of the sciatic nerve were performed using electron microscope. In immunohistochemical assays the content of NGF in the sciatic nerve after single or repeated administration of test drugs was assessed.

RESULTS

Microscopic examinations of the sciatic nerve revealed ultrastructural changes in nerve fibers indicating for neurodegenerative processes induced by CCI. Seven days after CCI surgery LPP1 and pregabalin reduced tactile allodynia in von Frey test (ED50 values were 1.5 and 15.4 mg/kg, respectively). None of the test drugs at dose range 0.5-100 mg/kg induced motor deficits in the rotarod test. In immunohistochemical assays repeated doses of pregabalin and LPP1 elevated NGF content.

CONCLUSIONS

LPP1 has antiallodynic properties and is an interesting lead structure in the search for novel analgesics used in neuropathic pain.

Determination of lipophilicity of γ-butyrolactone derivatives with anticonvulsant and analgesic activity using micellar electrokinetic chromatography

The lipophilicity of a library of 30 derivatives of dihydrofuran-2(3H)-one (γ-butyrolactone) was determined by MEKC. Calibration curve prepared for ten reference drugs enabled to calculate partition coefficient (log P) for novel compounds. The results of MEKC analysis were compared with lipophilicity coefficients determined by RP-TLC (R(M0)) and computational (Mlog P, Clog P) methods. Good correlation was observed between the results obtained by both experimental methods: the MEKC parameters log k and relative lipophilicity R(MO). The relationship between determined log P values and results of the computational prediction was weaker. Analysis of the relationship between lipophilicity and anticonvulsant activity showed statistically significant differences between mean values of log P coefficients for group of active (2.18) and inactive (1.51) compounds in the maximal electroshock test.

Evaluation of antinociceptive and antioxidant properties of 3-[4-(3-trifluoromethyl-phenyl)-piperazin-1-yl]-dihydrofuran-2-one in mice

The aim of this study was to evaluate the influence of 3-[4-(3-trifluoromethyl-phenyl)-piperazin-1-yl]-dihydrofuran-2-one (LPP1) on nociceptive thresholds in mouse models of persistent pain. Influence of LPP1 on motor coordination and its antioxidant capacity in mouse brain tissue homogenates were also assessed. Pain sensitivity thresholds in animals treated with LPP1 were established using 5 % formalin solution in normoglycemic mice and in streptozotocin (STZ)-treated diabetic mice in the von Frey, hot plate, innocuous, and noxious cold water tests (water at 10 °C and 4 °C, respectively). Motor deficits were assessed in the rotarod test, whereas antioxidant capacities were evaluated using ferric reducing ability of plasma (FRAP) assay, catalase (CAT), and superoxide dismutase (SOD) activities. LPP1was antinociceptive in both phases of the formalin test, in particular, in the late phase (at doses 0.9-30 mg/kg for 66-99 % vs. control normoglycemic mice) and in a statistically significant manner increased nociceptive thresholds in response to mechanical, heat, and noxious cold stimulation in neuropathic mice (at 30 mg/kg for 274, 192, and 316 %, respectively vs. diabetic control). LPP1 did not impair motor coordination of mice in the rotarod revolving at 6 or 18 rpm. In brain tissue homogenates, it demonstrated antioxidant capacity in FRAP assay and increased SOD activity for 63 % (acute administration) and 28 % (chronic administration) vs. control. No influence on CAT activity was observed. LPP1 has significant antinociceptive properties in the formalin model and elevates pain thresholds in neuropathic mice. It has antioxidant capacity and is devoid of negative influence on animals' motor coordination.

New imidazo[1,2-a]pyridines carrying active pharmacophores: synthesis and anticonvulsant studies

Five new series of imidazo[1,2-a]pyridines carrying biologically active pyrazoline (4a-e), cyanopyridone (5a, b), cyanopyridine (6a-f), 2-aminopyrimidine (7a-f) and pyrimidine-2-thione (8a-d) systems were designed and synthesized as prominent anticonvulsant agents. The target compounds were screened for their in vivo anticonvulsant activity following maximal electroshock (MES) and subcutaneous pentylene tetrazole (scPTZ) methods at a small test dose of 10 mg/kg. Further, Rotarod toxicity method was used to study the toxicity profile of selected compounds. Compounds 4b, 5a, 5b, 6a, 7e and 8d possessing 4-fluorophenyl substituent at 2nd position of imidazo[1,2-a]pyridine ring displayed potent anticonvulsant activity without displaying any toxicity. Enhanced activity profile was observed for new compounds in PTZ method over MES method.